PBOCEEDINGS OF THS POLYTECHNIC ASSCCIAT[KS. 403 



study and perfect the styles. These Clerks meet in convention once a year, 

 and decide what shall be the fashion for the ensuing Spring. Their 'busi- 

 ness is to arrange the general contour of the hat. 



After further remarks from Messrs. Fisher, Bartlett and Johnson, it was. 

 decided to continue the discussion of this subject, at the next meeting. — 

 Adjuurned. 



American' lyS Ti i ii E, Polttechnttc Associatio>', ) 

 Xovember IT, 1864. J 



Chairman, Professor S. D. Tillman: Secretary, Mr. Benj. Garvey. 

 The proceedings were opened by the Chairman, who read the following 

 summary of recent progress in science and art. 



Reduction of Silver Oezs. 



M. Poumarcde, in a communication to the French Academy, considers 

 that the loss complained of in reducing the rich ores of Mexico, is due to 

 an imperfect chloridization of the silver and the consequent irregularity of 

 action. If finely powdered quartz be mixed with one per cent of salt, and 

 heated for half an hour to redness in a covered crucible, all the silver will 

 be found to have passed into the form of chloride soluble in ammonia. If 

 the silver is in the form of a sulphide or any other compound, the result is 

 the same. The conversion into chloride takes place also when instead of 

 quartz, felspar is used either with or without earthy carbonates, oxide of 

 f iron or other constituents of the vein stone. 



Tee Electric Discharge. 



Experiments on the discharge of the Leyden jar have been made recently 

 by Mr. Fedderson of Leipsic. For analyzing the light, he employed a revol- 

 ving concave mirror silvered by Liebig's* process having a radius of curva- 

 ture of 500 millimeters. The rates of revolution are from 30 to 100 times 

 per second. With a short conducting circuit he found the discharge was 

 oscillatory — that is the current did not move in one direction but alternated 

 to and fro. As the resistance was increased the oscillaMon was diminished 

 and finally the current became continuous. If resistance- was still increased 

 from tlie point where the oscillations ceased, the duration of the discharge 

 was increased to i second point when the equilibrium is restored by means 

 jf partial sparks. The resistance in the last case was effected by means of 

 small tubes filled with (ftstilled water. The discharge from a short metallic 

 circuit he found lasted nearly one ten thousandth part of a second or about 

 one hundred times longer than the estimation made by Wheatstone. 



Light From the Pixed Stars. 



Dr. Miller and Mr. Huggins have presented to the Royal Society the 

 result of their examination of the light of some of the fixed stars by means 

 of the spectroscope. They found lines corresponding with them in the 

 ?pectrum of nine elementary bodies. They regard the difference in the 



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